1. Field of the Invention
The present invention relates to a track jump control apparatus and a track jump method. More specifically, the present invention relates to a track jump control apparatus and a track jump method, in which a target track number is set, a jump pulse corresponding to the target track number is applied to a tracking actuator driver, and a jump is performed one by one track by applying a first acceleration pulse or a deceleration pulse at a suitable timing to the tracking actuator driver until the target track number is reached, for example.
2. Description of the Prior Art
One example of such a kind of a track jump apparatus is disclosed in, for example, Japanese Patent Publication No. 7-48257 [G11B 7/085, G11B 21/08] published on May 24, 1995. In a multi-track jump circuit of this optical disk apparatus, as in a case of a DVD player “DVD-F2000” manufactured/marketed by the assignee of the present invention, each zero-cross interval time of a tracking error signal is measured, and if the measured time is delayed than a target time, an acceleration pulse is applied to a track access mechanism. In contrast, if the measured time is faster, a deceleration pulse is applied to the track access mechanism, whereby a moving speed of a beam is controlled at a constant speed while being jumped so that a track-jump is stably carried out.
However, in this prior art, since each of the acceleration pulse and the deceleration pulse is set at a constant width and a height (level), in a case that a moving speed of a disk becomes considerably faster than that of a beam (pick-up) due to a disturbance such as a vibration of a player main body, an eccentricity of the disk, etc., a moving direction of a pick-up, i.e. the objective lens against the disk becomes reversed (inverted). That is, as shown in FIG. 10(A), in a place where a pitch between adjacent tracks is considerably large due to an eccentricity of the disk, a zero-cross cycle of a tracking error (TE) signal becomes large as understood in FIG. 10(B). Therefore, where outputting an acceleration pulse having a constant width and a height, an acceleration is not sufficient, and therefore, the objective lens cannot catch up with the disk, thus resulting in an inverted moving direction of the pick-up (objective lens) with respect to the disk at a point indicated by P in FIG. 10(B). Therefore, there was a problem that the number of the tracks to jump is erroneously counted, and thus it is not possible to appropriately track-on to a desired (target) track.